This is a request for an ADAMHA Research Scientist Development Award (RSDA) to pursue a research program in Developmental Chronobiology with a specific focus on the chronobiology of aging. The circadian system, which strongly influences the occurrence and quality of sleep, is altered with aging. Due in large part to this age-related change in the circadian system, sleep disturbance is common among people over 65. Age-related sleep disturbance is exacerbated in geriatric depression, the most common psychiatric disorder affecting the elderly. Likewise, the significant sleep disturbance associated with shift work is aggravated in older workers. In both normal and depressed older people, sleep disturbance is a significant threat to the quality of life. For ten years, the candidate has focused on the elucidation of age-related alterations of the human circadian system, on the study of the impact of such changes on physiology and behavior, and on the development of approaches to alleviate the negative effects of circadian rhythms changes, particularly with regard to sleep disturbance. The immediate goal of this research is to examine further the efficacy of a non-drug treatment for age-related sleep disturbance using timed exposure to bright light, and to apply this promising treatment to other sleep-disturbed populations. The long-term goals of the research program include the detailed examination of the circadian systems of both normal and pathological aging, the application of circadian principles to the diagnosis and treatment of age-related pathophysiology, the enhancement of scientific expertise in geriatric psychiatry, and continuation of a training and education program in human chronobiology. The proposed research will use objective, physiological measures to track response to bright light treatments in groups of healthy elderly subjects and elderly, depressed outpatients. By studying healthy, sleep disturbed elderly for three months, it will be possible to assess the long-term efficacy of this bright light treatment, already shown to be effective in acute treatment protocols. The inclusion of geriatric depressives will make it possible to evaluate the efficacy of the treatment in a disorder often characterized by severe sleep disturbance. Similar procedures will be employed in a separate study to assess the effects of bright light interventions on sleep and performance in middle-aged subjects undergoing a simulated shift work protocol. The research program will be conducted in the Laboratory of Human Chronobiology, widely acknowledge to be one of the world's leading facilities for research related to human sleep and circadian rhythms. The candidate's recent appointment as Director of the Laboratory, and his recommended promotion to the rank of Associate Professor, reflect the Department of Psychiatry's commitment to the candidate's research focus and academic career. This Research Scientist Development Award will enable the candidate to develop and enhance the proposed research program by ensuring a basis of stable, long-term support.